Properties Of Denture Base Material Research Articles

Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials

In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO2) particles, while the second group consists of PMMA resin reinforced by (micro-lignin) particles.
 The mechanical tests performed in this research includedtensile test, compression test, impact test and hardness test. The results of this study showed that the values of tensile modulus of elasticity, compressive strength and hardness properties increased with increasing the volume fraction of these particles in PMMA composite materials. While, the values of tensile strength, elongation and impact strength properties decreased. Also, the addition of (nano-ZrO2) particles showed greater effect than that of (micro-lignin) particles in some properties of PMMA composite materials for prosthesis denture base materials specimens, while they have lower effect for the other properties.

Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials

In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO2) particles, while the second group consists of PMMA resin reinforced by (micro-lignin) particles.
 The mechanical tests performed in this research includedtensile test, compression test, impact test and hardness test. The results of this study showed that the values of tensile modulus of elasticity, compressive strength and hardness properties increased with increasing the volume fraction of these particles in PMMA composite materials. While, the values of tensile strength, elongation and impact strength properties decreased. Also, the addition of (nano-ZrO2) particles showed greater effect than that of (micro-lignin) particles in some properties of PMMA composite materials for prosthesis denture base materials specimens, while they have lower effect for the other properties.

Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials

In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO2) particles, while the second group consists of PMMA resin reinforced by (micro-lignin) particles.
 The mechanical tests performed in this research includedtensile test, compression test, impact test and hardness test. The results of this study showed that the values of tensile modulus of elasticity, compressive strength and hardness properties increased with increasing the volume fraction of these particles in PMMA composite materials. While, the values of tensile strength, elongation and impact strength properties decreased. Also, the addition of (nano-ZrO2) particles showed greater effect than that of (micro-lignin) particles in some properties of PMMA composite materials for prosthesis denture base materials specimens, while they have lower effect for the other properties.

The Effect of Addition of Combination of Plasma Treated Polyester and Polyamide Fibers on Surface Roughness and Some Mechanical Properties of Heat Cured Acrylic Resin

Background: Poly (methyl methacrylate) has several disadvantages (poor mechanical properties) like impact and transverse strength. In order to overcome these disadvantages, several methods were used to strengthen the acrylic resin by using different fibers or fillers. This study was conducted to evaluate the effect of Plasma treatment of the fiber on mechanical properties Poly (methyl methacrylate) denture base material. Materials and methods: Specimens were prepared from poly methyl metha acrylic (PMMA) divided according to present of fiber into 4 groups (first group without fiber as control group, second group with Plasma treated polyester fibers, third group with Plasma treated polyamide fibers and fourth group Plasma treated combination of polyester and polyamide fibers. The samples to be treated with oxygen gas plasma Results: the results show that the highest mean values for all tests included in the study appeared in group IV (Plasma treated combination of polyester and polyamide fibers) except for the surface roughness test the highest mean values found in group III (Plasma treated polyamide fibers, and only polyamide fiber slight improved roughness and other group have no effect on surface roughness Conclusion The addition of plasma treated fiber ( polyester, polyamide and combination of both fiber) improve transverse, impact strength and hardness properties of denture base material and has no effect on surface roughness.

Reinforcement of polymethyl methacrylate denture base resin with ZnO nanostructures

AbstractPolymethyl methacrylate‐zinc oxide (PMMA/ZnO) nanocomposites with different ZnO morphology and quantities were prepared by in situ curing of MMA/PMMA used in denture base material in the presence of ZnO nanostructured materials. The composition, structure, and morphology of the nanocomposites were characterized by Fourier‐Transform infrared spectra (FT‐IR), X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The effect of ZnO morphology and contents on the mechanical properties including impact, flexural, and hardness was studied. The results demonstrated that the mechanical and thermal properties of denture base materials were improved by incorporation of nano‐sized ZnO into the polymethyl methacrylate matrix. The impact strength was highly improved upon using ZnO nanotubes. However, the flexural strength was improved using ZnO nanospheres.

SEM Evaluation of Denture Base Materials Used in Clinical Practice

Removable dentures aim to improve masticatory function, esthetics and phonetics. Different materials have been used as denture base materials but poly(methyl methacrylate) (PMMA) is most frequently used in most countries. Surface related properties of denture base materials (roughness, surface free energy, wettability, hydrophobicity, etc.) are of clinical importance since they affect plaque accumulation and staining. Surface roughness specifically influences the adhesion and retention of Candida Albicaans, which has a particular importance in denture-induced stomatitis pathogenesis. Bacterial plaque retention directly affects oral hygiene even if the patient achieves an appropriate cleaning of the denture. Ideally, denture base materials should be smooth so plaque adherence is reduced or even avoided. Test specimens of four heat polymerized materials were obtained by a classical press-pack dough molding technique of 1.5 mm thick wax-plate flasked in class III Moldano followed by the recommended polymerization regime. One of the materials was processed through a fast polymerization cycle. Injection-type materials were automatically produced using a dedicated injection unit. All plates were sectioned in 10 mm x 10 mm samples. No finishing protocol was applied. The selected specimens were examined under field emission scanning electron microscope (SEM). A large variation of surface topography was recorded between materials. There were visual differences between the four heat polymerized resins but also between the two injection-type materials. Surface topography was also influenced by the polymerization regime. Within the limitations of our study, we found that surface topography is influenced by the chemical composition of each material, the heat cure cycle and the processing method.

Studying the effect of addition a composite of silanized Nano-Al2O3 and plasma treated polypropylene fibers on some physical and mechanical properties of heat cured PMMA denture base material

Background: Polymethyl methacrylate (PMMA) is the most commonly used material in denture fabrication. The material is far from ideal in fulfilling the mechanical requirements, like low impact and transverse strength, poor thermal conductivity. The purpose of this study was to evaluate the effect of addition a composite of surface treated Nano Aluminum oxide (Al2O3) filler and plasma treated polypropylene fiber (PP) on some properties of denture base material. Materials and methods: One hundred fifty prepared specimens were divided into 5 groups according to the tests, each group consisted of 30 specimens and these were subdivided into 3 groups (unreinforced heat cured acrylic resin as control group),reinforced acrylic resin with( 0.5%wt Nano Al2O3 and2.5%wt plasma treated PP fibers) group and reinforced acrylic with(1%wt Nano Al2O3 and 2.5%wt plasma treated PP fibers group).The tests were impact strength, transverse strength, indentation hardness(shore D), surface roughness thermal conductivity. The results were statistically analyzed using ANOVA test. Results: A highly significant increase in impact strength, surface hardness, thermal conductivity with the addition of 0.5%wt. (Al2O3) and 2.5%wt PP fiber to(PMMA),also there is a significant increase in surface roughness and non significant increase in transverse strength. At the concentration of 1%wt nano (Al2O3) and 2.5%wt PP fiber there is a highly significant increase in impact strength surface hardness and thermal conductivity. Non-significant differences were shown in transverse strength and significant increase in surface roughness. Conclusion: The addition of a composite of Al2O3 nanoparticles and PP fiber to PMMA improves the impact strength, surface hardness and thermal properties, surface roughness while non-significant difference in transverse strength.

Effect of sodium fluoride on the properties of acrylic resin denture base material subjected to long-term water immersion

Background: Fluoridated acrylic resin material can present more stable properties when compared with conventional one.The most widely used fluoride –containing substance added to dental resin materials is sodium fluoride (Naf). This study evaluated the effect of Naf in different concentration to the acrylic resin denture base material and its effect on tensile strength ,modules of elasticity with long –term water immersion (after 4 months immersion in de-ionized water) Materials and methods: Eighty specimens from dumbbells shaped metal pattern for tensile strength test were preparedaccording to ISO 527: 1993 plastic –Determination tensile properties ,in dimensions(60mm, 12mm, 3 ± 0.2mm) length, width and depth respectively were allocated to two groups according to water immersion there were 40 specimens before immersion and 40 specimens after water immersion for 4 months in de-ionized water(the de-ionized water was changed every day),these two groups were sub divided in to four groups according to the concentration of Naf,Naf powder were added to monomer of acrylic in concentrations of 1%,2%and 5% Naf .0% Naf(control group) ,then mixing were done with polymer according to manufacture instructions ,the conventional flasking ,packing procedure were used following that (fast cycle). For tensile strength test the measuring was done by Instron machine,the values of modulus of elasticity were obtained from tensile test . Results: Results showed that the addition of sodium fluoride to acrylic resin material werelower the tensile strength and modules of elasticity with highly significant differences p 0.05), and for modules of elasticity between control and 1%Naf, 1% Naf and 2%Naf( after immersion ),there was only significant differences between them(p<0.05). Conclusions: Addition of fluoride to acrylic resin material lower the tensile strength and modules of elasticity when compared to control group regardless the concentration of Naf, But after immersion (for 4 months ) the tensile strength and modules of elasticity increased in comparison to groups before immersion (with highly significance differences p <0.01).

Evaluation of the effect of sodium fluoride addition on some mechanical properties of heat cure acrylic denture base materials

Background: The geriatric patients wearing removable partial dentures are increasing in proportion. At the same time, the root caries prevalence accompanied by gingival recession is increasing. A variety of vehicles can deliver fluoride into the oral cavity, including fluoride mouth-rinse, fluoride dentifrice, topical fluoride, and fluoride-releasing restorative materials, all of which effectively prevent root caries and suppress recurrent caries. This study aimed to evaluate the effect of sodium fluoride addition on some mechanical properties of heat cure acrylic denture base material. Material and method: A total of 90 samples were prepared in this study, then divided into three main groups according to the type of test used (hardness, tensile and transverse strength tests). Each main group was subdivided into three main subdivisions according to percentage of sodium fluoride addition to the heat cure acrylic denture base material (control no addition, 2%NaF ,and 5%NaF sodium fluoride groups) Results: The sodium fluoride addition to acrylic denture base materials showed slight but non significant increase in transverse strength and tensile strength tests while the results showed significant and highly significant differences for 2%NaF and for 5%NaF shore D hardness groups respectively. Conclusions: Addition of 2% and 5% sodium fluoride to heat cure acrylic resin is considered advantageous as the mechanical properties of resin denture base materials in respect to hardness tensile and transverse strength were not adversely affected.

Perspectives for Titanium-Derived Fillers Usage on Denture Base Composite Construction: A Review Article

Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong. They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in aqueous oral environment because of the hydrolytic degradation of silica-based fillers and silane-coupling agents. The clinical problem of using silanes in adhesion promotion is bond degradation over time in oral environment. In addition, silanes do not bond effectively to nonsilica-based dental restorative materials. This review presents titanium-derived fillers as alternatives to siliceous fillers. Titanate-coupling agents are found to be effective couplers in treating Ti-based fillers because of their chemical compatibility and relatively high stability in aqueous environment.

Novel acrylic resin denture base with enhanced mechanical properties by the incorporation of PMMA-modified hydroxyapatite

A kind of novel acrylic resin denture base enhanced by PMMA-modified hydroxyapatite (M-HAP) was prepared and the modification effect of HAP on the mechanical properties of denture base material was investigated in the present study. HAP whiskers were prepared by hydrothermal homogeneous precipitation process and were silanized by the coupling agent, 3-methacryloxy propyl trimethoxyl silane (γ-MPS), to induce the vinyl groups onto its surface. Methyl methacrylate (MMA) were then modified outside the vinyl functionalized HAP via polymerization to build a similar chemical structure with the acrylic matrix. A novel acrylic resin denture base was obtained through self-curing process with the incorporation of this PMMA-modified HAP, and the content of which ranged from 0wt% to 0.8wt%. Thermal gravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and universal testing apparatus were used to characterize M-HAP and corresponding denture base. The results showed that PMMA were successfully grafted onto the surface of HAP whiskers with up to 15wt% and the modification turned out to be useful for the dispersion and compatibility of whiskers in the acrylic resin matrix. The mechanical properties of the prepared denture base samples were enhanced greatly after incorporating with M-HAP fillers. The optimal incorporated content of M-HAP was also investigated.

Influence of chlorine dioxide on the physical properties of denture base materials

Influence of chlorine dioxide on the physical properties of denture base materials

Effect of Mica Reinforcement on the Flexural Strength and Microhardness of Polymethyl Methacrylate Denture Resin

Conventional denture base polymethyl methacrylate (PMMA) is low in strength, soft, and brittle on impact. Improvements in the mechanical properties of denture base materials have been sought by adding different reinforcing phases to the PMMA matrix. The purpose of this work was to study the effects of mica reinforcement on the mechanical properties, flexural strength, and microhardness of PMMA denture base resin. Wet ground muscovite mica and Lucitone 199 original shade denture base resin were used. Two micas were tested: W200 and P66 with average particle sizes (d50) of 131 μm and 30 μm, respectively. The mica was silane treated in a solution of 3-methacryloxypropyl trimethoxysilane, ethanol, and water, and then dried. The specimens were fabricated using the denture base resin manufacturer's instructions with a powder : liquid ratio of 21 g/10 ml and a mixing time of 30 seconds. Five treatment groups were produced with differing amounts of mica added to the PMMA denture base resin: (A) control group with 0 vol% mica, (B) 10 vol% W200 mica, (C) 20 vol% W200 mica, (D) 10 vol% P66 mica, (E) 20 vol% P66 mica. The mica replaced equal volumes of the PMMA powder component to minimize changes in viscosity. The three-point bending flexural strength specimens were 70 × 11 × 3 mm(3) . Seven specimens were prepared for each treatment group. The hardness specimens were prepared from the ends of the three-point bend specimens after they were broken (N = 7). After deflasking, the specimens were polished with 600 grit silicon carbide paper to achieve smooth surfaces. A standard three-point bending jig with a span length of 50 mm was attached to an Instron universal testing machine. The specimens were placed on the jig, and loading was carried out using a 1 mm/min crosshead speed until failure. Microhardness was measured using a Clark microhardness tester with a Knoop indenter. The load was set to 200 g and the dwell time to 15 seconds. ANOVA and Tukey tests were used for statistical analyses (Alpha = 0.05). The flexural strength of the control group was between 77% and 94% higher than all the mica-containing groups (p≤ 0.05). No significant differences were found within the four mica groups. Microhardnesses of the 20% mica groups (both fine and coarse) were 33% and 26% higher than the control (p≤ 0.05). The 10% mica groups had higher hardness than the control group, but the increase was not statistically significant (p > 0.05). Mica additions to denture PMMA reduced flexural strength; however, with the specimens containing highest mica concentrations (20%), microhardness significantly increased.

The effect of autoclave processing on some properties of heat cured denture base material

Although most of the physical and mechanical properties of denture base resin polymerized by the conventional heat polymerization have been studied, the effect of autoclave processing in these properties has not been fully determined. The aim of the present study is to investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of acrylic denture base material. Materials and methods: Vertex was the heat- cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: Control groups (Group A) in which acrylic resins processed by conventional water- bath processing technique (74°C for 1.5 hours then boil for 30 minutes) and experimental groups in which acrylic resins processed by autoclave at 121°C,210KPa.The experimental groups were divided into Group B(Fast) for15min. , and Group C (Slow) for 30min... To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. Results: There were no significant differences between the results of the processing techniques regarding transverse, impact, and hardness tests. While, there were a highly significant difference in porosity test results. Conclusions: The autoclave processing technique might also be a good alternative to the conventional water bath processing technique. Regarding to autoclave processing technique, the slow (long) curing cycle provide better denture bases material including the tested physical and mechanical properties as compared with the fast (short) curing cycle.

Effect of Al2O3/ZrO2 Hybrid on the Fracture Toughness and Flexural Properties of PMMA Denture Base

The investigation of ceramic filler on the properties of denture base materials made from PMMA filled with Al2O3/ZrO2 was carried out. The amount of Al2O3/ZrO2 filler was fixed at 5 wt%. However, the ratios of Al2O3 to ZrO2 added were varied from 0 to 100. Samples were prepared for fracture toughness and flexural test. The findings were analyzed using scanning electron microscopy (SEM). The findings were recorded that the Al2O3/ZrO2 ratios show higher fracture toughness and flexural properties than PMMA matrix. SEM micrographs indicate that distribution of Al2O3 and ZrO2 in the PMMA matrix is fairly homogeneous. The mixing method was good between reinforcement particles and PMMA matrix. Therefore, addition of six ratios of Al2O3/ZrO2 with PMMA and this mixture is able to improve the mechanical properties of this denture base material.

Effect of Al2O3/ZrO2 reinforcement on the mechanical properties of PMMA denture base

A study on the properties of denture base materials made from PMMA filled with Al2O 3/ZrO2 was carried out. The amount of Al2O 3/ZrO2 filler was fixed at 5 wt%. However, the ratio of Al 2O3 to ZrO2 added was from 0 to 100. Samples were prepared for fracture toughness, flexural, and tensile tests. The fracture surface was analyzed using SEM and EDS. It was found that the Al2O 3/ZrO2 of 80 : 20 ratio shows the highest values of fracture toughness and flexural properties. SEM micrographs indicate that distribution of Al2O3 and ZrO2 in the PMMA matrix is fairly homogeneous. The interface between the reinforcement particles and matrix is good. Therefore, addition of Al2O3/ZrO2 in PMMA improves the mechanical properties of this denture base material.

Effect of rigid rod polymer filler on mechanical properties of poly-methyl methacrylate denture base material

Objectives The aim of this study was to evaluate the mechanical properties of denture base material with rigid rod polymer (RRP) particulate fillers. Methods Specimens were fabricated from autopolymerized polymethylmethacrylate denture base resin (Palapress Heraus-Kulzer) and RRP particles were used as fillers (Parmax Mississippi Polymer Technologies, Inc.). Five groups were tested: 0 wt% RRP, 10 wt% RRP, 20 wt% RRP, 30 wt% RRP, and 100 wt% RRP. Specimens were stored dry at room temperature for 2 days or in water at 37 °C for 44 days before testing until failure at a three point bending test (ISO 1567) for measuring flexural properties. The surface microhardness, water sorption, and solubility were also measured. Existence of interpenetrating polymer network (IPN) between filler and denture resin was examined using solvent treatment and scanning electron microscopy (SEM). Results Specimens with RRP filler revealed higher flexural modulus, but the flexural strength decreased. Specimens with 30% RRP filler showed flexural strength of 67.4 MPa, whereas specimens without fillers gave strength of 93.9 MPa. The 100% RRP group revealed the highest flexural strength (305 MPa). Flexural strength of water-stored test specimens decreased in most groups when compared to dry specimens. Microhardness increased as a function of RRP filler. SEM micrographs revealed no IPN-network on the surface of RRP fillers. Addition of RRP fillers decreased the water sorption, whereas solubility was not affected. Significance This study revealed that although RRP polymer has good mechanical properties, addition of RRP to denture base resin as fillers did not increase mechanical properties. This was explained by lack of IPN-formation between RRP fillers and polymer matrix.

Effect of Methacrylated Hyperbranched Polymers on the Fracture Properties of Denture Base Materials

Hyperbranched polymers have the potential to reinforce crosslinked polymeric materials. In this study several concentrations of a methacrylated hyperbranched polyether are formulated with a denture base resin and cured. The denture base resin is a polymethyl methacrylate based resin. The fracture toughness of each of these concentrations was measured and compared to control. Only the 1% concentration had a significantly higher fracture toughness compared to the control. This is similar to other results that are found in the literature.

The reinforcement of dentures.

The material most commonly used for the fabrication of complete dentures is poly (methyl methacrylate) (PMMA). This material is not ideal in every respect and it is the combination of virtues rather than one single desirable property that accounts for its popularity and usage. Despite its popularity in satisfying aesthetic demands it is still far from ideal in fulfilling the mechanical requirements of a prosthesis. The fracture of dentures may be due to the mechanical properties of the acrylic resin or may be due to a multiplicity of factors leading to failure of the denture base material. Generally, there are three routes which have been investigated to improve the impact properties of PMMA: the search for, or development of, an alternative material to PMMA; the chemical modification of PMMA such as by the addition of a rubber graft copolymer; and the reinforcement of PMMA with other materials such as carbon fibres, glass fibres and ultra-high modulus polyethylene. The following review of attempts to improve the mechanical properties of denture base material takes account of papers published during the last 30 years.

The effect of the curing cycle upon the molecular weight and properties of denture base materials

The two-phase dough-moulded system using PMMA has become the almost universal method of manufacturing dentures. Despite its popularity, however, the material has some inherent weaknesses, the most important being a low resistance to fracture. Many parameters can be varied during denture fabrication and may affect the properties and performance of the dentures. This investigation examines the effect of the polymerization cycle on the molecular weight of denture base systems and reports upon the influence of the molecular weight on mechanical properties. It is demonstrated that polymerization using different PMMA powders and curing cycles generally produced higher molecular weight values in the two-phase products than in the original powder phase. However, the molecular weight distributions were essentially similar. Denture base systems with weight average molecular weights >10 5 displayed optimum fracture strength properties. A comparison between dental two-phase heterogeneous PMMA material and industrial homogeneous PMMA bulk polymerized systems demonstrated that industrial structures with w<dental heterogeneous structures exhibited superior properties. Whilst the study demonstrated differences in the fracture strength of the materials tested these differences cannot be expected to have a clinical relevance in view of denture in-service stress levels.